Harmonized Mexican Health and Aging Study (Harmonized MHAS) is an easy-to-use version of data from the first 5 waves of the Mexican Health and Ageing Study (MHAS) with a set of harmonized variables suitable for cross-country analysis. Using the RAND HRS and Harmonized HRS as models, Harmonized MHAS defines variables as identically as possible with the RAND HRS and Harmonized HRS to allow users to compare variables with all other Harmonized data sets. Documentation for each variable in Harmonized MHAS, including a description of its creation, the MHAS variables used, and descriptive statistics, is detailed in the Harmonized MHAS codebook.